The present invention relates to a flexible composition suitable as a material for electric resistor elements or varistor elements. More particularly, the present invention relates to a composition composed of a polymeric material as the matrix and a finely dispersed phase of a metalic silicon dispersed in the matrix in such an amount that the shaped body of the composition may have a desired electroconductivity exhibiting very stable characteristic relationships between the applied voltage and the current passing therethrough regardless of the highly flexible condition of the shaped body.
There are hitherto known various kinds of flexible resistor materials shaped with a composition prepared by dispersing an electroconductive or semiconductive finely divided material in a matrix having flexibility such as rubbers and certain kinds of plastics. These materials are used as a resistor element or as a varistor element and widely used in a variety of applications where flexibility of the material is essential as being subjected to bending or under vibration.
One of the serious problems in these flexible materials is that the resistance performance of the material, i.e. the relationship between the voltage applied to the shaped body thereof and the electric current passing therethrough, is not always sufficiently stable, especially, when the shaped body is subjected to bending or used under vibration.
The reason for the above mentioned undesirable phenomenon is presumably that the insulating polymeric material as the matrix and the electroconductive or semiconductive phase finely dispersed therein, which may be a metal or a semiconductor, have relatively poor affinity in the interface therebetween owing to their so much diversified surface properties causing unstable interfacial condition when the shaped body of the composition is subjected to bending or under vibration. This problem is more serious when the dispersed phase is made of a semiconductor which requires to be incorporated in the matrix in a relatively large amount by volume in order to impart a sufficiently high electric conductivity to the shaped body to be used as a resistor element or as a varistor element.
Various attempts have been made to solve the above described problem but with no satisfactory results.